DE102005058808B4 - Position measuring device with holographic scale - Google Patents
Position measuring device with holographic scale Download PDFInfo
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- DE102005058808B4 DE102005058808B4 DE102005058808.5A DE102005058808A DE102005058808B4 DE 102005058808 B4 DE102005058808 B4 DE 102005058808B4 DE 102005058808 A DE102005058808 A DE 102005058808A DE 102005058808 B4 DE102005058808 B4 DE 102005058808B4
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- 230000000737 periodic effect Effects 0.000 claims abstract description 20
- 230000002452 interceptive effect Effects 0.000 claims 1
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- 238000005286 illumination Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
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- 238000004364 calculation method Methods 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
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- 238000010276 construction Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/36—Forming the light into pulses
- G01D5/38—Forming the light into pulses by diffraction gratings
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/0005—Adaptation of holography to specific applications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D2205/00—Indexing scheme relating to details of means for transferring or converting the output of a sensing member
- G01D2205/90—Two-dimensional encoders, i.e. having one or two codes extending in two directions
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/0005—Adaptation of holography to specific applications
- G03H2001/0033—Adaptation of holography to specific applications in hologrammetry for measuring or analysing
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/0005—Adaptation of holography to specific applications
- G03H2001/0066—Adaptation of holography to specific applications for wavefront matching wherein the hologram is arranged to convert a predetermined wavefront into a comprehensive wave, e.g. associative memory
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
- G03H1/30—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique discrete holograms only
- G03H2001/303—Interleaved sub-holograms, e.g. three RGB sub-holograms having interleaved pixels for reconstructing coloured holobject
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Transform (AREA)
Abstract
Positionsmessgerät mit einer Laserlichtquelle (1) und einem Abtastkopf (3) mit Photodetektoren (7), die Laserlicht (8) der Laserlichtquelle (1) empfangen, sowie mit einem Mittel (2, 6) zum Erzeugen eines periodischen Lichtmusters (10) auf einer Abtastplatte (4), dadurch gekennzeichnet, dass die Abtastplatte (4) ein aus wenigstens zwei flächig ineinander verschachtelten Teilhologrammen (A, B, C, D) zusammengesetztes Hologramm (H) trägt, wobei die Teilhologramme (A, B, C, D) einfallendes Laserlicht (8) in Richtung der den Teilhologrammen (A, B, C, D) jeweils zugeordneten Photodetektoren (7) beugen. Position measuring device comprising a laser light source (1) and a scanning head (3) with photodetectors (7) receiving laser light (8) of the laser light source (1) and means (2, 6) for generating a periodic light pattern (10) on one Scanning plate (4), characterized in that the scanning plate (4) carries a hologram (H) composed of at least two partial nested sub-holograms (A, B, C, D), the sub-holograms (A, B, C, D) incident laser light (8) in the direction of the sub-holograms (A, B, C, D) each associated photodetectors (7) bow.
Description
Die Erfindung betrifft ein Positionsmessgerät, bei dem durch die Verwendung holographischer Strukturen ein besonders einfacher Aufbau gegeben ist und das dennoch sehr genau messen kann.The invention relates to a position measuring device, in which a particularly simple structure is given by the use of holographic structures and yet can measure very accurately.
Die Verwendung von Beugungsstrukturen in optischen Positionsmessgeräten ist bekannt. Ganz allgemein werden positionsabhängige periodische Lichtmuster durch den Einsatz von Beugungsgittern erzeugt und abgetastet, um so positionsabhängige periodische Detektorsignale zu erzeugen.The use of diffractive structures in optical position measuring devices is known. More generally, position-dependent periodic patterns of light are generated and scanned by the use of diffraction gratings to produce position-dependent periodic detector signals.
Die
Die
Die
Die
Aufgabe der Erfindung ist es, ein einfach aufgebautes Positionsmessgerät anzugeben, das kostengünstig herstellbar ist und dennoch eine gute Signalqualität aufweist.The object of the invention is to provide a simply constructed position measuring device, which is inexpensive to produce and yet has a good signal quality.
Diese Aufgabe wird gelöst durch eine Vorrichtung mit den Merkmalen des Anspruches 1. Vorteilhafte Ausführungsformen ergeben sich aus den Merkmalen, die in den von Anspruch 1 abhängigen Ansprüchen aufgeführt sind.This object is achieved by a device having the features of claim 1. Advantageous embodiments result from the features that are listed in the dependent of claim 1 claims.
Es wird ein Positionsmessgerät mit einer Laserlichtquelle und einem Abtastkopf mit Photodetektoren beschrieben, der Laserlicht der Laserlichtquelle empfängt. Dieses Positionsmessgerät weist außerdem ein Mittel zum Erzeugen eines periodischen Lichtmusters auf der Abtastplatte auf. Die Abtastplatte trägt ein aus wenigstens zwei flächig ineinander verschachtelten Teilhologrammen zusammengesetztes Hologramm, wobei die Teilhologramme einfallendes Laserlicht in Richtung der den Teilhologrammen zugeordneten Photodetektoren beugen.A position measuring device with a laser light source and a scanning head with photodetectors, which receives laser light from the laser light source, is described. This position measuring device also has a means for generating a periodic light pattern on the scanning plate. The scanning carries a hologram composed of at least two partially interleaved sub-holograms, the sub-holograms bending incident laser light in the direction of the photodetectors associated with the sub-holograms.
Durch die Bewegung des Lichtmusters relativ zur Abtastplatte erhält man periodische Detektorsignale mit einem hohen Modulationsgrad. Die Anordnung ist bei geeigneter Auslegung verschmutzungsunempfindlich.The movement of the light pattern relative to the scanning is obtained periodic detector signals with a high degree of modulation. The arrangement is insensitive to contamination with a suitable design.
Weitere Vorteile sowie Einzelheiten der vorliegenden Erfindung ergeben sich aus der nachfolgenden Beschreibung bevorzugter Ausführungsformen anhand der Figuren. Dabei zeigt
-
1 ein Positionsmessgerät für eine Messrichtung, -
2 zwei Hologramme, -
3 eine Detektorebene des Positionsmessgerätes, -
4 ein Positionsmessgeräte für zwei Messrichtungen, -
5 eine alternative Ausführungsform zur Erzeugung eines periodischen Lichtmusters.
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1 a position measuring device for a measuring direction, -
2 two holograms, -
3 a detector plane of the position measuring device, -
4 a position measuring device for two measuring directions, -
5 an alternative embodiment for generating a periodic light pattern.
Bei dem Hologramm H handelt es sich um ein binäres Amplitudenhologramm. Solche Hologramme ermöglichen es, Licht aus einem kohärenten Laserstrahl gezielt in ein beliebiges reales Bild zu beugen. Sie lassen sich z.B. durch die rechnerische Überlagerung einer Referenzwelle mit den (fiktiven) Punktlichtquellen des gewünschten Bildes berechnen. Für jede einzelne Teilfläche des Hologramms H wird in einem Raster mit z.B. 1µm Schrittweite die Summe beispielsweise der Feldvektoren des elektromagnetischen Feldes der Punktlichtquellen bestimmt. Je nach Größe des resultierenden Feldes wird bei Amplitudenhologrammen die jeweilige Teilfläche dann undurchlässig oder transparent gewählt. Das Hologramm wird einfach durch die Strukturierung einer nichttransparenten Schicht auf einer transparenten Platte hergestellt.The hologram H is a binary amplitude hologram. Such holograms make it possible to diffract light from a coherent laser beam into any desired real image. They can be e.g. calculated by the mathematical superimposition of a reference wave with the (notional) point light sources of the desired image. For each individual sub-area of the hologram H, in a raster with e.g. 1μm step determines the sum of, for example, the field vectors of the electromagnetic field of the point light sources. Depending on the size of the resulting field, the respective sub-area is then selected opaque or transparent in amplitude holograms. The hologram is made simply by patterning a nontransparent layer on a transparent plate.
Für ein binäres Phasenhologramm, das gegenüber dem Amplitudenhologramm eine höhere Effizienz aufweist, benutzt man eine Reliefstruktur mit zwei Ebenen, die für die Wellenlänge des Referenzstrahls eine Phasenverschiebung von 180° zueinander aufweisen. Die Phasenverschiebung erreicht man entweder durch das gezielte Tiefätzen einer transparenten Platte (z, B. Glas) oder durch die Strukturierung einer transparenten Schicht auf einer Platte. Im Vergleich zu binären Phasenhologrammen kann man die Effizienz weiter erhöhen, wenn man anstelle der zwei Ebenen mehrere Stufen mit kleineren Phasenverschiebungen benutzt. Zur Berechnung solcher Hologramme werden in der Regel komplexere Algorithmen eingesetzt.For a binary phase hologram, which has a higher efficiency compared to the amplitude hologram, one uses a relief structure with two planes, which have a phase shift of 180 ° to each other for the wavelength of the reference beam. The phase shift can be achieved either by the targeted deep etching of a transparent plate (z, B. glass) or by structuring a transparent layer on a plate. Compared to binary phase holograms, efficiency can be further increased by using multiple stages with smaller phase shifts instead of the two levels. To calculate such holograms, more complex algorithms are usually used.
Die Rekonstruktion des gewünschten Bildes erfolgt, indem man das fertige Hologramm mit dem Referenzstrahl beleuchtet. Licht aus dem Referenzstrahl wird aufgrund der Amplituden- oder Phasenstruktur des Hologramms in das reale Bild gebeugt.The reconstruction of the desired image is done by illuminating the finished hologram with the reference beam. Light from the reference beam is diffracted into the real image due to the amplitude or phase structure of the hologram.
Für das in der linken Hälfte der
Das Hologramm H wird natürlich rein rechnerisch generiert: Sowohl die Berechnung der vollständigen Teilhologramme A, B, C, D, als auch deren Zerlegung in Streifen und das Zusammensetzen des Hologramms H aus diesen Streifen erfolgt mit einem Computer, der als Ausgabe beispielsweise eine CAD-Datei liefert, mit der ein Elektronenstrahlschreiber das Hologramm H der rechten Hälfte der
Der Maßstab
Die vier Positionen des Maßstabes, in denen jeweils nur ein Teilhologramm A, B, C, D beleuchtet wird, sind in
Es ist auch möglich, ein Gitter
Wie
Das in der
Die in der zweiten Hälfte des Hologramms H angeordneten Teilhologramme A', B', C', D' sind um 90 Grad gegenüber denen der ersten Hälfte gedreht und nicht in Messrichtung X nebeneinander, sondern übereinander angeordnet. Dies entspricht einer Nebeneinanderanordnung in Messrichtung Y. Die in dieser zweiten Hälfte beleuchteten Teilhologramme A', B', C', D' beugen das Licht abwechselnd auf die Photodetektoren
Von Vorteil ist, wenn jeweils mehrere Perioden des Hologramms H durch mehrere Perioden des periodischen Lichtmusters
Eine Referenzmarke zur Codierung der absoluten Position kann erzeugt werden, indem auf der Abtastplatte
Es kann auch ein Hologramm für mehrere unterschiedliche Wellenlängen erzeugt werden, das einfallendes Licht verschiedener Wellenlängen in jeweils unterschiedliche Richtungen beugt. Beleuchtet man so ein Hologramm gleichzeitig mit Licht mit mehren Wellenlängen, lässt sich z.B. auch so eine Referenzmarke realisieren.It is also possible to generate a hologram for several different wavelengths, which diffracts incident light of different wavelengths in different directions. If one illuminates such a hologram simultaneously with light with several wavelengths, e.g. also realize such a reference mark.
Für den Aufbau eines hier beschriebenen Positionsmessgerätes ist es nicht notwendig, dass die Detektoren
An einem Versuchsaufbau gemäß
Claims (6)
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DE102005058808.5A DE102005058808B4 (en) | 2005-12-09 | 2005-12-09 | Position measuring device with holographic scale |
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DE102005058808.5A DE102005058808B4 (en) | 2005-12-09 | 2005-12-09 | Position measuring device with holographic scale |
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DE102005058808B4 true DE102005058808B4 (en) | 2019-02-21 |
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CN107741689A (en) * | 2017-11-12 | 2018-02-27 | 湖北器长光电股份有限公司 | The apparatus and method that flash lamp rising angle and light distribution are determined based on holographic dry plate photochemical effect |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57203902A (en) * | 1981-06-10 | 1982-12-14 | Nec Corp | Optical position detector |
JPS57203905A (en) * | 1981-06-10 | 1982-12-14 | Nec Corp | Optical position detector |
JPH01280215A (en) | 1987-10-27 | 1989-11-10 | Okuma Mach Works Ltd | Optical encoder |
US5678319A (en) * | 1995-03-04 | 1997-10-21 | Dr. Johannes Heidenhain Gmbh | Index grating having partial fields that are geometrically offset in the measuring direction |
US5909283A (en) | 1997-10-07 | 1999-06-01 | Eselun; Steven Albert | Linear encoder using diverging light beam diffraction |
US20010017350A1 (en) | 2000-02-15 | 2001-08-30 | Kou Ishizuka | Optical encoder |
DE10334250A1 (en) | 2003-07-27 | 2005-02-24 | Samland, Thomas, Dipl.-Math. | Two dimensional position measurement unit for machine tools has measurement rod with pairwise differentiated code field types diffracting ray to separate receive sampling fields |
-
2005
- 2005-12-09 DE DE102005058808.5A patent/DE102005058808B4/en not_active Expired - Fee Related
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57203902A (en) * | 1981-06-10 | 1982-12-14 | Nec Corp | Optical position detector |
JPS57203905A (en) * | 1981-06-10 | 1982-12-14 | Nec Corp | Optical position detector |
JPH01280215A (en) | 1987-10-27 | 1989-11-10 | Okuma Mach Works Ltd | Optical encoder |
US5678319A (en) * | 1995-03-04 | 1997-10-21 | Dr. Johannes Heidenhain Gmbh | Index grating having partial fields that are geometrically offset in the measuring direction |
US5909283A (en) | 1997-10-07 | 1999-06-01 | Eselun; Steven Albert | Linear encoder using diverging light beam diffraction |
US20010017350A1 (en) | 2000-02-15 | 2001-08-30 | Kou Ishizuka | Optical encoder |
DE10334250A1 (en) | 2003-07-27 | 2005-02-24 | Samland, Thomas, Dipl.-Math. | Two dimensional position measurement unit for machine tools has measurement rod with pairwise differentiated code field types diffracting ray to separate receive sampling fields |
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